Generally, a display device such as a television (TV), a digital television (DTV), a personal computer (PC), and the like is provided with various functions owing to the rapid technical developments. In particular, in case that at least two still image files captured by a digital camera or the like are stored, the demand for a display device capable of displaying the still image files sequentially tends to rise. In this case, the function of displaying the still image files sequentially can be named a slide show function or more.